Somebody has a girlfriend before marriage, and after marriage, he is also in a relationship with other ladies. One of them gives birth to a baby from this man. The man has kids from his wife as well. After a long time of marriage, now the wife knows everything. At the same time, the man said he will leave everything like this. The wife is not satisfied though.
She is asking what should she do? Should she leave her husband or stay with him for the sake of her children? The wife is upset that if the baby of another lady becomes an adult, he/she will claim the father. What should she do? What does Islam say for this couple? What should they do to the baby? The man has given him/her his family name.
بِسْمِ اللهِ الرَّحْمنِ الرَّحِيْم
In the name of Allah, the Most Gracious, the Most Merciful
Fornication and adultery is a great sin in the eyes of Allah (SWT).
Allah (SWT) says-
وَلَا تَقْرَبُوا الزِّنَا ۖ إِنَّهُ كَانَ فَاحِشَةً وَسَاءَ سَبِيلًا
“And do not approach unlawful sexual intercourse. Indeed, it is ever an immorality and is evil as a way.” (Surah al-Israa, Verse 32)
This man has greatly broken the trust of the wife by having a relationship with another woman while he is married.
The wife has a choice to stay in the marriage or to leave him. If she is confused about what she wants to do, she should pray Salatul istikhara and make a lot of dua and ask Allah (SWT) to guide her to what is best. If she decides to stay with this man, then they need to resolve any issues they still have and the trust between them. It would be advisable that they seek an Islamic marriage counsellor to help them.
In terms of the children born from zina, they will not take the father’s lineage, rather the lineage of the mother. This means they can only inherit through the mothers side alone and do not inherit from the father.
Only Allah knows best
Answered by Alimah Nasima Umm Hamza
Checked and approved by Mufti Mohammed Tosir Miah
Darul Ifta Birmingham
 Ibn Abideen, Raddul Muhtaar, Volume 6, Page 777